Circular saws have various types of arbors or drives. A circular saw can only use saw blades that matches the arbor. Common saw blade arbors include round arbors and diamond arbors. Some saw blades are manufactured with knockout portions, which allow a blade to be used with different arbors. For example a saw blade with a round arbor may have a knockout portion that can be removed to allow the saw blade to be used on a diamond arbor. The knockout portions are difficult to remove without damaging the blade or knocking it out of true. Saw blades need to run true without the slightest hint of a wobble. Many times a screw driver, wrench, hammer or any other tool that is lying around is used to remove the knockout portion. The knockouts are difficult to remove with these tools because they have not been designed to remove the knockout portions. Even if the user is successful at removing the knockout, the blade could be damaged or the knockout is only partially removed, which makes it even more difficult to remove. This procedure can also be dangerous due to the sharpness of the saw blades, which could result in the injury of the user attempting to remove the knockout.